The present invention relates to fluid dispensers, particularly to dispensers for chemical fluid samples, and more particularly to a micromachined chemical jet dispenser whereby chemical fluid samples can be precisely ejected in size, location, and time.
Many chemistry experiments require the manipulation of small chemical samples in large numbers. Often crude pipetting or wet needle drop transferring is done with robotic drop handlers for increased parallelism.
Micromachining of various components, particularly silicon, is being actively pursued in various fields of technology. This micromachining technology is generally referred to as micro-electro-mechanical systems (MEMS); and one of the later applications of this technology is the extremely successful computer printer ink jet print head, which is a silicon based microstructure based on the heated bubble jet concept.
Many applications exist for a highly improved method of dispensing miniature chemical droplets where heating is not allowed; and new opportunities will arise in the fields of molecular biology, clinical laboratories, environmental laboratories, and the chemical industry. Thus, there is a need to enable dispensing of fluid chemical samples rapidly as well as precisely in location, size, and time under computer control. Miniaturized chemical experiments by the thousands can be rapidly done with such a dispensing device, this being amenable to multiple processes requiring many combinatorial and/or sequential chemical reactants to be combined or just placed, separately or jointly, for subsequent processing or analysis. For example, the human genome program has ideal applications for such a dispenser. The arraying of transformed bacterial colonies carrying DNA of chromosome 19 onto 8.times.12 cm nylon filters is a significant bottleneck (currently &gt;3 hours for 45 nylon filters) to the research, as it is currently done with a slow robotic needle dipping method. Other biomedical applications for such a dispenser include synthesis of DNA oligomers and injection into multichannel electrophoresis experiments.
The above-mentioned needs and resolution of the above dispensing problems are satisfied by the present invention, which constitutes a micromachined chemical jet dispenser. This invention fills this type of need in a manner similar to the above-referenced ink jet print heads but without heat damage to the samples. The device of this invention enables the production of large (.about.100), dense linear arrays (.about.50 channels/cm) in a manner that is stackable, thus further enabling the generation of two dimensional arrays of chemical samples, with micro precision; droplets in the range of 10-200 .mu.m are feasible. The efficiency of the drop dispensing device of this invention is much greater than current non-monolithic technologies can allow, and it is ideally suited to computer control and robotics systems.